You'll Always Need Family
by GoldGuardian2418
Summary: Triple crossover of Big Hero 6, Teenage Mutant Ninja Turtles, and Ben 10. When Donnie's birthday passes with no one's acknowledgement, he runs away and meets up with the Big Hero 6, who are fighting a battle against Ultron. Can they stop Ultron and will Donnie return to his family? Find out!


**An early birthday request for Shinigamilover2, whose birthday is in a few days. Here you go, Amigo! Enjoy and Happy Birthday!**

**Teenage Mutant Ninja Turtles and their characters belong to Nickelodeon, Big Hero 6 and its characters belong to Disney, and Ultron belongs to Marvel and Disney. The Holiday Village from Ben 10 belongs to Cartoon Network and Man Of Action, as does Ben 10.**

**I own nothing in this story.**

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**You'll Always Need Family**

Donnie trudged his way over the bridge that led to the city of San Fransokyo, a city that was brighter than New York, at least to him.

He leaned tiredly on his bo staff. He had trudged through several states to get here, mostly using the trains by hopping on them and being silent. It was certainly faster and he didn't have to worry about others spotting him.

The sixteen year old ninja turtle sighed, thinking about April and how worried she'd be, but he just couldn't take the pressure from his brothers to make something that would help against the Kraang and to be quick on it. He had been working tirelessly on something, but on the day of his birthday, he had decided to take some time off from working on his project. But even though he had, his brothers hadn't liked it and none of them even acknowledged his birthday, they just berated him on not working on that project which would have been finished after one more day and would have been ready for a battle that had taken place that afternoon.

Now, almost a full day had passed since then and Donnie was very upset. "They don't even appreciate me and I'm the one with the brains," he said to himself sadly.

When the train stopped, he jumped down and quickly blended with the shadows, moving quietly until he heard a grunt and something yellow flew past him, hitting a wall and falling down with a groan. Something colored a purplish pink with some orange soon joined the first one.

"Hiro! Gogo and Honey Lemon are down!" yelled a voice.

Curious, Donnie looked around the wall corner and saw a three-eyed dragon, a black kid with green armor and blue swords that looked like lasers, and a smaller kid in purple armor riding on the back of a robot that looked like a powerhouse with his red and purple armor. They were battling robots that looked like elves and watching them while fighting the robot and the kid was someone Donnie first thought was a giant mouser, but then looking at him more closely, it only looked like a mouser, only very ugly.

The robot fired out some lasers and one hit the small boy. Seeing the others were too far away to catch the boy in time, as the boy was headed for some sharp metal that was sticking out from where a building had been demolished, Donnie grabbed his bo and used it as if he was an Olympic pole vaulter, streaking through the air and catching the boy while dropping to the ground in a roll. He took the brunt of the fall, but was unhurt and checked on the boy. "You okay?" he asked him.

Hiro gave a start. "Whoa, what are you?" he asked.

"Hiro!" called Baymax who came down to them. "Are you injured?"

"No, I'm fine, Baymax," said Hiro.

They heard a grunt as Wasabi took a harsh hit and landed beside them. Hiro quickly checked to see if he was alright as Donnie looked up at the robot and then at Baymax.

"Hiro, right?" he asked.

"Yeah?"

"Think Baymax can get me up there to fight that robot?"

Realizing the turtle knew their names from earlier, Hiro nodded. "Baymax, get…uh," he paused when he realized he didn't know the turtle's name.

"Donatello. Donnie for short," Donatello told him helpfully.

"Thanks. Baymax, get Donatello up there. I'll check on Honey Lemon and Gogo," said Hiro.

Baymax nodded and waited until Donatello was on his back before taking off. The purple-masked turtle held on as they came up on the robot, who turned to them.

"You fools are becoming a pain," he said in an evil robotic voice.

"Man, you make the mousers seem like ants," said Donatello as he jumped up and managed to hit the evil robot, who fell down and couldn't get any laser shots because the turtle was too fast.

"My elves, retreat back to Holiday Village!" he said. "I, Ultron, declare that we'll return soon!"

With that, Ultron opened a portal and he and the robotic elves vanished into it.

Donnie and Baymax got down to the others. Fred came up supporting Honey Lemon and Gogo while Hiro helped Wasabi stand up. "Man, that guy really gave our armor a pounding," said Wasabi.

"He's gotten stronger with those robotic elves," said Honey Lemon.

"We need to get to the source and stop them," said Hiro.

Donnie stepped up. "Uh, sorry to sound clueless, but who or what was that guy?" he asked.

"He's Ultron," said Fred. "He's a creepy robot from another dimension who is bent on conquering other worlds."

"We think he was attracted to the advanced robotics our city has," said Honey Lemon.

"We've been fighting him for weeks, but he's gotten a bit stronger, especially with those freaky elves," said Gogo.

"Sounds a bit like the Shredder," said Donnie.

"You mean the creep who is terrorizing New York along with the…what are those creepy brainy things called again?" asked Wasabi.

"The Kraang," the ninja turtle supplied helpfully. "My brothers and I have been fighting them, the Shredder, and whatever villains Shredder sends at us."

"Wait," said Fred. "You're one of those super cool ninja turtles!"

Donnie blinked. "You've heard of us?" he asked.

"Who hasn't? You guys are awesome!"

Donnie gave an embarrassed laugh as the others laughed lightly before Hiro spoke up.

"Come on, guys. Let's get our armor fixed up. I think we'll be seeing Ultron again sooner than later," he said.

"Could I come too?" asked Donnie. "I could help you all out."

The Big Hero 6 team looked at each other and then nodded in unison. "Sure!" said Hiro. "Follow us."

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They were soon at the Big Hero 6's base and Donnie, being a whiz with technology like the others, helped them fix their armor and make it better. He immediately became best pals with Wasabi, Gogo reminded him of Leo with how serious she always was but also how dedicated she was, he instantly liked Honey Lemon, who reminded him of Mikey with how chipper she was. It seemed nothing got her down for long. He thought Fred was maybe a bit undisciplined, but saw how dedicated he was to the team and Hiro reminded him of himself, being the geek and knowing how technology worked and learning how to better utilize it. And Baymax was the team's medic and the one to give pep talks.

The seven of them swapped stories as they worked and laughed with each other, but the whole time, Donnie was reminded of his family and he began to miss them and wish they were there. He knew his brothers would have liked these kids and Splinter would have no doubt been glad to see young minds making a difference.

That evening, the others had turned in, but the purple-masked turtle was unable to sleep and so was looking at the city from the window. It looked so much like New York. April would have loved this.

He now hung his head and heard a slight noise behind him. "Donatello?" asked Baymax. "Your neurotransmitter levels are low, indicating you are sad. Conclusion: You are upset over the fact that your day of birth passed with no one's acknowledgement of it."

Donnie gave a weak chuckle. "Wow, Hiro wasn't kidding about you being thorough," he said. "But yeah, I am upset about that. I feel so unappreciated by my brothers, but we're fighting a war just like you guys. I guess pressure can make life seem like it's going to end soon."

"Donatello, I'm sure your brothers appreciate you, even when you have disagreements," said Baymax. "Hiro and Tadashi, my creator, sometimes had disagreements, but they always appreciated each other."

The robot's words hit Donnie hard as he remembered the countless fights he and his brothers had had over the years, but they always stuck together and worked out the problems. He now faced Baymax.

"Thanks, Baymax," he said. "You're right. I guess I got so wallowed up in my own hurt feelings that I wasn't thinking straight."

Baymax blinked. "Your neurotransmitter levels are climbing. Does this mean you feel better?" he asked.

Donatello smiled and laughed a little. "Yeah, I am," he said and then did something he saw Hiro do earlier.

He hugged Baymax and the robot returned the hug before seeing the turtle yawn. "You are tired," he said.

"Yeah," Donnie agreed. "I'm going to hit the sack. See you in the morning, Baymax."

"See you in the morning, Donatello," said Baymax before powering down.

* * *

The next morning, Ultron struck again, this time having several hundred robotic elves with him and he even had a hostage.

The Big Hero 6 were stunned with horror when they saw Cass in Ultron's grasp and he had her tied up. "Surrender," said Ultron. "Or you'll never see her again."

"No! Aunt Cass!" Hiro cried out, feeling a bit helpless.

Donatello glared at Ultron. "Heroes never surrender!" he said. "Guys, go for it!"

Realizing he meant the plan, the Big Hero 6 jumped into action. Gogo and Fred started on the robotic elves, demolishing them with both fire and speed. Wasabi plowed through the robots with his laser swords. Donatello, Honey Lemon, Hiro, and Baymax entered the portal where they saw the elves coming out and saw the machine making them. It didn't take long for them to surround the machine and destroy it and the robotic elves from within, but then the machine suddenly began shaking and beeping.

"Self-destruct sequence!" Donnie yelled. "We need to clear out! Now!"

"Baymax!" Hiro called and the red-armored robot quickly grabbed them all and flew out just in time for the machine to explode and the portal to close up.

"Nooo!" Ultron cried out and tried to blast them, but Honey Lemon used some of her special balls and trapped him. Ultron was furious and escaped through another portal, but couldn't get Honey Lemon's chemical sludge off him, making them all laugh.

"That'll teach him to mess with us," said Donnie confidently.

"You bet!" said Fred with a whoop of joy.

After things had settled down, Donatello grabbed his things. "Well, I need to get back to New York," he said. "My brothers and I still have to stop the Kraang and Shredder."

"We'll miss you, buddy," said Hiro.

The purple-masked turtle smiled. "I'm sure I'll be able to visit," he said. "Maybe I'll convince my brothers to come."

Honey Lemon suddenly gave Donnie a kiss on the cheek. "Thanks for everything," she said. "You're awesome, for a ninja turtle."

That made him blush a little before he accepted hugs from them all. "Take care, guys. Good luck," he said as he jumped the train back to New York.

The ride back seemed quick to Donnie as he came up with other plans to stop the Kraang and Shredder and soon he was headed down to the lair, where his brothers and father surprised him with a birthday party. Even April was there.

Being back with his family made him happy as he realized one thing the Big Hero 6 had taught him.

You'll always need your family, because that's what matters the most when problems come your way.

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**GoldGuardian2418**


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